“She’s saying, ‘Please take me with you,’ ” said Ms. Massaro, 63, who then spied the shop owner slipping into his office — the container portion of a box truck — and scolded him about the dog’s condition. He refused her request to take the dog.

Gina was emaciated several years ago, when Ms. Massaro had her spayed and vaccinated. The dog is healthier now, but Ms. Massaro said, “This is modern-day slavery — she’s a slave.”

For more than 20 years, Ms. Massaro has roamed industrial areas in some of New York City’s roughest neighborhoods, caring for junkyard dogs — animals on guard duty that are chained or penned up and often underfed.

“I prefer to call them working dogs,” she said while feeding a noisy Rottweiler on a salvage lot in the Willets Point section of Queens. The dog seemed hostile, and Ms. Massaro carefully pushed food into the squalid pen surrounded by stacks of car doors, mufflers and other parts on the oily, muddy ground.

She sometimes manages to find new homes for these animals, as well as for “working cats” kept by deli owners for rodent control, “enslaved by owners and betrayed by humane organizations,” which, she claims, tend to ignore poorer areas.

“When people ask me why I do it, I tell them, ‘Because you don’t do it,’ ” said Ms. Massaro, whose group, the Spay Neuter Intervention Project, or SNIP, arranges for spaying, neutering and vaccinations.

Ms. Massaro, a retired word processor for a Manhattan law firm, said she supported the group largely with her own pension checks. Finding the animals better homes sometimes requires some creativity, as with the scrawny black cat she pulled from the streets of Brownsville and installed as the mascot of a Liberty Avenue social club that was well known as a mob hangout.

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Driven by a reporter on a recent weekday, Ms. Massaro started by picking up a shopping cart full of food at Pet Supplies Plus in Maspeth, the Queens neighborhood where she lives. After feeding Gina, she spied a scraggly cat across from a bodega and then heard more meowing.

“Somebody’s crying,” she exclaimed, sounding like a protective mother, and she followed the sound to the basement entrance of a residence. She opened the sidewalk doors and pulled out a second skinny cat by the scruff of its neck. A tenant came out and under interrogation by Ms. Massaro, insisted that he had no idea how the cat wound up trapped in the basement. “He’s lying,” she said flatly, after telling him she would be back to have the cats neutered.

At a homeless shelter on Eastern Parkway, she bristled when a worker told her that he “got rid of” feral cats on the property.

“The only thing I get rid of is my garbage,” she snapped.

Ms. Massaro grew up on the Lower East Side. Her twin sister died at birth, and she became the oldest of four girls.

“When I was a teenager, my mother threw my father out on the street, and I would see him on my way to school,” she recalled. She worked to get him social services and housing in a nearby men’s shelter.

“I learned at an early age how to deal with the system and fight for services,” she said — a vital skill for rescuing animals.

She was married at 18, had a daughter at 20 and divorced soon afterward, she said. Her relationships since then have not lasted, not like her love affairs with countless underserved animals on the city streets.

On into the evening, she plodded through Willets Point, feeding cats, asking after certain stray dogs, and grilling groups of grease-smeared workers about animals’ whereabouts.

“How about the rooster that was here, where is he?” she asked a mechanic, who said he did not know.

“Yeah, I bet,” she said and headed to the next animal waiting for her help.